Back to EveryPatent.com
United States Patent | 6,097,688 |
Ichimura ,   et al. | August 1, 2000 |
A recording/reproducing apparatus for an optical recording medium which is used for recording and/or reproducing information on/from the optical recording medium by irradiating the optical recording medium with a laser light using two-group objective lenses comprising at least two lenses as the first and second lenses, is provided so as to comprise a light source emitting the laser light, the first lens for focusing the laser light emitted from the light source, the second lens arranged between the first lens and the optical recording medium, and a device for moving both the first and second lenses relative to each other to change the distance between them in the optical axis direction of the laser beam, so that the moving device moves the second lens to change the distance between the first and second lenses. Consequently, this invention can provide the recording/reproducing apparatus with a larger numerical aperture (NA) and reduce the influence of spherical aberration on the light beam to realize high density recording/reproducing of information signals.
Inventors: | Ichimura; Isao (Kanagawa, JP); Maeda; Fumisada (Tokyo, JP); Yamamoto; Kenji (Saitama, JP); Ohsato; Kiyoshi (Chiba, JP); Watanabe; Toshio (Kanagawa, JP); Fukumoto; Atsushi (Kanagawa, JP); Suzuki; Akira (Kanagawa, JP) |
Assignee: | Sony Corporation (Tokyo, JP) |
Appl. No.: | 811727 |
Filed: | March 6, 1997 |
Mar 15, 1996[JP] | 08-058870 |
Current U.S. Class: | 369/112.24; 369/44.14; 369/44.23 |
Intern'l Class: | G11B 007/09 |
Field of Search: | 369/54,112,44.14,43,44.23 359/664 |
5764613 | Jun., 1998 | Yamamoto et al. | 369/44. |